Process for ingot casting employing a magnetic field for reducing macrosegregation and associated apparatus and ingot

摘要

A process of reducing macrosegregation in the casting of a metal alloy ingot is disclosed. The process includes introducing a molten metal alloy into a casting mold cavity, cooling the molten metal alloy to form a solid zone, a liquid-solid mushy zone overlying the solid zone, a liquid zone overlying the liquid-solid mushy zone and a melt surface on the liquid zone, employing during the cooling at least one substantially static magnetic field having at least two planes of symmetry which intersect on the longitudinal axis of the ingot, generating the magnetic field by at least one coil means having an inner region through which the metal alloy passes, energizing the coil means by a substantially static electrical current wherein the current follows a path defined by the coil means and passes around at least one of the molten metal alloy and the zones, improving the strength and uniformity of the magnetic field by at least one ferromagnetic flux path, and dampening convection flows of the molten metal alloy which cause macrosegregation by means of the magnetic field. An associated apparatus suitable for casting metal alloys and an improved ingot having a refined equiaxed grain structure and a reduced pore size are provided.